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Graft Site (graft + site)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

Radioguided Parathyroidectomy for Recurrent Hyperparathyroidism Caused by Forearm Graft Hyperplasia,

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2003
Rebecca S Sippel
Abstract One of the surgical options for symptomatic secondary hyperparathyroidism is a total parathyroidectomy with forearm implantation. Recurrence can occur and is most likely caused by hyperplasia of the small fragments of parathyroid tissue implanted in the forearm muscle. Forearm graft hyperplasia can be detected using Tc-99m sestamibi scanning of the forearm, which can show abnormal enhancement at the former graft site. In this report, we present the case of a 49-year-old gentleman with recurrent hyperparathyroidism caused by hyperplasia of forearm graft fragments. Unfortunately, no sutures or clips were placed at his initial surgery to identify the location of the parathyroid tissue in the forearm. Thus, we describe the first reported use of radioguided techniques using Tc-99m sestamibi injection and intraoperative gamma probe to localize parathyroid fragments in the forearm muscle. During our initial exploration, we found that injection of the tracer in the operative arm leads to prohibitively high levels of background activity. During a second exploration, the tracer was injected in the lower extremity, minimizing the background in the forearm and allowing the gamma probe to clearly identify two areas of abnormal parathyroid tissue. The intraoperative radioprobe allowed quick identification and removal of the abnormal parathyroid tissue in a case that was made particularly challenging by the absence of marking sutures. [source]

Role of IFN, in Allograft Tolerance Mediated by CD4+CD25+ Regulatory T Cells by Induction of IDO in Endothelial Cells

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 11 2007
P. Thebault
Regulatory T cells have been described to specifically accumulate at the site of regulation together with effector T cells and antigen-presenting cells, establishing a state of local immune privilege. However the mechanisms of this interplay remain to be defined. We previously demonstrated, in a fully MHC mismatched rat cardiac allograft combination, that a short-term treatment with a deoxyspergualine analogue, LF15-0195, induces long-term allograft tolerance with a specific expansion of regulatory CD4+CD25+T cells that accumulate within the graft. In this study, we show that following transfer of regulatory CD4+T cells to a secondary irradiated recipient, regulatory CD25+Foxp3+ and CD25+Foxp3, CD4+T cells accumulate at the graft site and induce graft endothelial cell expression of Indoleamine 2, 3-dioxygenase (IDO) by an IFN,-dependent mechanism. Moreover, in vivo transfer of tolerance can be abrogated by blocking IFN, or IDO, and anti-IFN, reduces the survival/expansion of alloantigen-induced regulatory Foxp3+CD4+T cells. Together, our results demonstrate interrelated mechanisms between regulatory CD4+CD25+T cells and the graft endothelial cells in this local immune privilege, and a key role for IFN, and IDO in this process. [source]

Islet Allograft Rejection by Contact-Dependent CD8+ T cells: Perforin and FasL Play Alternate but Obligatory Roles,

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 8 2007
M. Sleater
Though CD8+ T lymphocytes are important cellular mediators of islet allograft rejection, their molecular mechanism of rejection remains unidentified. Surprisingly, while it is generally assumed that CD8+ T cells require classic cytotoxic mechanisms to kill grafts in vivo, neither perforin nor FasL (CD95L) are required for acute islet allograft rejection. Thus, it is unclear whether such contact-dependent cytotoxic pathways play an essential role in islet rejection. Moreover, both perforin and CD95L have been implicated in playing roles in peripheral tolerance, further obscuring the role of these effector pathways in rejection. Therefore, we determined whether perforin and/or FasL (CD95L) were required by donor MHC-restricted (,direct') CD8+ T cells to reject islet allografts in vivo. Islet allograft rejection by primed, alloreactive CD8+ T cells was examined independently of other lymphocyte subpopulations via adoptive transfer studies. Individual disruption of T-cell-derived perforin or allograft Fas expression had limited impact on graft rejection. However, simultaneous disruption of both pathways prevented allograft rejection in most recipients despite the chronic persistence of transferred T cells at the graft site. Thus, while there are clearly multiple cellular pathways of allograft rejection, perforin and FasL comprise alternate and necessary routes of acute CD8+ T-cell-mediated islet allograft rejection. [source]

Pulsed erbium:YAG laser-assisted autologous epidermal punch grafting in vitiligo

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 11 2000
Mukta Sachdev MD
Background A pilot study was conducted to evaluate the efficacy and safety of pulsed erbium:YAG laser ablation of autologous minipunch grafted sites for the treatment of refractory or stable vitiligo. Methods Thirteen patients, seven men and six women, aged between 19 and 58 years, with Fitzpatrick skin types ranging from type IV to VI, were grafted. The pulsed erbium: YAG laser was used to create recipient graft sites. Results Repigmentation was observed in 12 out of 13 patients. Failure of grafts to repigment ranged from 3% to 100%. No untoward side-effects of surgery were noted. Conclusions Using an erbium:YAG laser to create graft recipient sites permits the survival of punch harvested grafts and the spread of pigmentation to the surrounding skin. [source]

Surface modification of nylon-6 fibers for medical applications

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2007
S. E. Shalaby
Abstract Hydroxyethylmethacrylate (HEMA) is considered to be one of the important vinyl monomers. The ability of polyhydroxyethyl-methacylate (PHEMA) graft sites to consecutive chemical modification makes the use of nylon-6 fibers grafted with PHEMA a feasible bed for immobilization of a wide range of biologically active reagents, specially enzymes, drugs, cells, and immunadsorbents. Stemming from the above discussions, in this article, the graft copolymerization of HEMA onto modified nylon-6 fibers containing Polydiallyldimethylammonium chloride (PDADMAC) in the presence of Cu2+,K2S2O8 as a redox initiating system was carried out, with very high rate and almost without homopolymer formation. The factors affecting the grafting reaction (monomer, K2S2O8 and cupric ion concentrations, the amount of PDADMAC as well as the reaction temperature) were studied. Kinetic investigation revealed that the rate of grafting (Rp) of HEMA onto modified nylon-6 fibers is proportional to [HEMA]1, [CuSO4.5H2O] 0.7, [PDADMAC]0.4, and [K2S2O8]1.4. The overall activation energy was calculated (71 KJ/mol). The fine structure, surface topography, thermal and electrical properties of parent and grafted nylon-6 fibers were investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3788,3796, 2007 [source]